Pneumatic tire and the like.



W. J. THOROLD. ,PHBUMATXC TIRE AND THE LIKE.

AHLIGATIOR, nun mm a, 190e.

Patented Fes. 22,190.

WILLIAM JAIUSS THOHOLD. 0F LONDON, ENGLAND.

PNEUBATIC TIRE AND THE LIKE.

Specification of Letters Potent. Patented Feb, 22, 1 91()` Application filed I une 8, 1908, Serial No. 437,410.

To nimm if. may concern: y

Re it known that l'.jlYiLLiA\i JAMES 'inw nono. a subject of the King of Great-Britain und Ireland. residing at. S70-93 Fleet street, in the city of. LEI-loo. England, have inventuen' and u improvement in and ing tc j'cneunmtic "lires and the Like,

of which th: follow is u speciiicution.

'The present invention relates to pneumatic tires 2nd 4the. like and comprises an iruproved method of and ui-cans for rendering Y1e nir tubes of pneuinfit lc tires or the covers tl creo in such ceses 'when the air tubes arc anspensccl with. capable .of ntoniatically .ingtr up uni' puncture. or incision caused therein :intl so preventing; the escape of the contained comprssed nia'.

Sin-re the commercial introduction o pneumatic tires for road vehicles many devices, methods, and changements have been invented having for their object the Yprevention of the escape of the air romeuli tires in the event of the :iirrtuhes thereof becoming puncturcfl or. delmged. 'ltjhgis Vbeen proposed for instancetininjee't into the air tubes ot pneumatic tires viscous substances suoli es molasses or glycerin, or gelatin, glue soga .starch and dexiiin compounds; or so luions, either aqueous or nlf:olu'. licq of gums or resins but none o such substances or com pounds has been satisfactory in use and that for: :x variety of reasons some of which are smiiciently obvious as not to need further discussion. More feasible propositions bave also been put forward involying the use of an inner viscous lining for the air tube formed from raw or purtially vulcanized indio-rubber or rubber con'ipound. Many such propositions have been commercially tried and have niet with e certain measure of success. but owing to the hitherto insuperable dill -ultjf experience-i in retaining sut-li inner Y I u linings in their original cliective condition,

such `self-healing" tubes have fallen into desuetude.

New, to the present invention, which Abelongs to that class of self-healing tubes -lsly described, use is made of ,a particular solvent for the miv rulihcr employed. The solution or'oonipound so produced and when ud ln the manner hereinafter described allows of the production of an inner air for pneumatic tires which is per fectly efficacious in automatically sealing up :my ordinary incision or puncture and effectually overcomes the disadvantages liith erto experienced with an air tube of this trpe- In the accompanying drawing which illustrates this invention, the ligure is a view in transverse section of an air tube embodying the present invention The preferred const ructionl of an air tube l for a pneumatic tire according lto the present invention comprises an outer tube a of vulceniz-ed india-rubberas usual, an inner tubeI or lining b of partially vulcanized rubber or rubber compound, and a further inner lining c composed of pure rubber held in sus ension within the solvent employed. This as: inner lining c which is the essence of this present invention is put into the tbbe in the form of a solution.l

The solvent vhich is employed is a crude gas tot benzene having n high boiling point. ,The particular benzene employed must also have the following characteristics-(11) specific gravity at, C., .890; (b) refrac.

tive index M* C., 1.5060; (c) distilling between 125`C. and 180? C., and (Il) flash point (open {est} 105O I". The usual coal tar solvent nphtiia having a boiling point of about LOOQL. to 1.40o C. is useless for the .present invention and according to my exiI pcricnce success depends upon the employment of a benzene solvent which boils from '125 C. to 180 C. for which purpose the proportion of hydrocarbons of bollino' below 120 C. must be relatively small.

It has been ascertained by long-continued experiment that a suitable solution for the point present invention comprises pure para rub.

ber 4.3% und solvent 95.7%.

The preferred method of introducingv the solution to form the innermost liningr of the tube is as follon'ss-Tlie lined tube is made in the way above-described and completed with the exce tion of the insertion of the usual vulve. lirough the 'hole into which the valve is'subseqnently fitted is poured n quantityof the above-described solution. The quantity of solution employed will obviously depend on the size of the tube and the thickness of the liningl desired, but the preferred amount is such tlnit the linished lining is from' `1/8 to 3/16 of nn inch in :thickness over the entire interior surface.

After the solution is poured in, the tube is rapidly revolved nlernntely in different diruftwns until tlxe solu'uun 1s equally listributed over lie entire inerm surface. The rerulving Should be repeated al imei'- vnas nf eight hours` during the ensuing 455 hours tu prevent the solurima settling in any pnrxieulnr parl, of the ubs it iS essential that the finish-il lining should be, of an equal ibid-:nwe over ille entire interior surface. .'li the expiration uf the 1S hours a. pprtion 0l' the solution ill lune becume dis Dated by evupomtinn und the tube is than ready 'nr the fitting (if the vulve and lien lor use.

EDWARD S. GEORGE, R. Wnsmcorr. 

